Nanotechnology for colorectal cancer detection and treatment

Table 2 Screening methods for colorectal cancer

Ref.	Screening methods
[18-20]	Stool tests	Kit-based technique; guaiac-based fecal occult blood test uses guaiac to detect heme; FIT uses antibody to detect hemoglobin in stool; FIT-DNA test detects hemoglobin and DNA biomarkers in the stool
		Non-invasive, low cost, colon cleansing is not required, non-bleeding tumors cannot be detected
[21,22]	Flexible sigmoidoscopy	Flexible tube with light, lens for viewing and tool for removing tissue; rectum and lower third of the colon screened to detect polyps, cancer or other abnormalities
		Sedation is required; accurate detection if polyps and cancers are present; unable to detect polyps or any abnormalities present in cecum, ascending colon hepatic flexure, or on transverse colon; colon cleansing is required
[23,24]	Colonoscopy	Flexible tube light with a lens for seeing and a tool for excising the abnormal tissue; entire colon and rectum are screened for cancer by inserting the colonoscope through anus
		Sedation is required; visualization of entire inner lining of the colon and rectum; minute polyps can be detected; sedation may lead to bleeding or tear of the intestinal wall; sedation may lead to bleeding or tear of the intestinal wall
[25-27]	Computed tomography colonography	X-ray based computed tomography scanner captures two- and three-dimensional images of the entire colon; computer assembles these pictures into detailed images
		Sedation is not required in this method; non-invasive; colon cleansing is not essential; may miss small polyps
[28]	Double-contrast barium enema	X-ray images are then captured by introducing barium sulphate enema
		Examination of the whole colon and the rectum; sedation is not required; for the patient who cannot undergo standard colonscopy, this method is useful; colon cleansing is very necessary for this method; otherwise, it will give false positive results

FIT: Fecal immunochemical test.